Jeremiah D. Vallotton

Pye Farm: Sample Archive and Notes on Farm

At Pye farm, samples were taken in five blocks, four large ones (λ, θ, Π, Φ) and one small (Ω). As I sampled, I took notes on the farm fields, which are included below. I also took copious pictures of every sampling location, which illustrates the soil profile differences by sampling location.

Rough map of grid sampling scheme for Pye Farm. Fields were subdivided into theta, pi, lamda, omega, and phi sections, then sampled in rows. Each point represents two samples (two depths) at one spatial location. Omega was the most recently converted portion of the farm but was not sampled intensively since it was never farmed, only cleared.

Below are the archives of photographs of the soils profiles and surrounding soil for all five of the subdivisions of the farm:

The first portion (rows A-D) were very uniform, with even coverage of a rhizomal grass. However, starting with λD03, a new soil emerged that would be present until λJ: what appeared to be a muck histisol overlying a sandy illuviated layer with oxidative colours and occasionally an elluviated layer as well.


This muck was purest and least intermixed with sand to 6 in. than other samples. It is easy to see why strawberries thrive without management in this soil. Interestingly, towards the southern end of the fruit patch (rows λG and λH), the muck disappeared and regular podzols reeemerged, and in these sections, the strawberries were weaker or dead.


The grasses in rows λJ, λK, λL, and λM often were rich in organic matter, very dark in color, and similar to a muck or mollisol.


While heavily dominated by sand, there were occasionally clay areas in the 15-30cm horizon, but rarely.


Colour was highly variable; moving from λA towards λM, the colour of the illuviated subsoil shifted from an orange to increasingly red, with some samples the same deep, dusky red colour of oxisols, though very sandy (parent material?). (Editor’s note: Dr. Unc mentioned that this layer is a special feature of podzols; this is illuviated iron that has hardened into an impermeable layer; I found that striking it with my soil knife shattered it into regular sand).


0-15 cm was almost always a single organics-rich horizon, brown to black, while 15-30cm was almost always a combined illuviated and elluviated layer with more colour variability (white, tan, red, orange, yellow, some black). Occasionally, the upper horizon extended into the 15-30cm range, giving it more dark organic soil, while the converse was also rarely true.

This section was on higher ground, with sandier and more uniform soils than anywhere else on the farm (partly comparable to λA- λC but few other places).

It also had far less ground cover and less signs of organic matter in the soil profile, in places hardly able to support plant life beyond some mosses and other small plants. These were identified by another scientist as typical low fertility bog plants, indicating that, despite the conversion of this land to agriculture, the soil remained incapable of supporting plants beyond bryophytes (very low fertility).

A local professor explained this by pointing out that this land and that of θ, which was closest to the river, was likely former riverbed five thousand years ago (and within a hundred metres or less of the current riverbed). The high spots (φ), with their high sand and low fertility, were likely sand banks, while the low areas (mollisolic θ) were likely low spots in the river where organic matter settled out, over time creating the high C soils I observed.

The grasses in the southern rows (C+D) had similar features to adjacent grasses in section λ: dark and rich 15+ cm layer of organic matter, overlying usually an illuviated red layer, rarely with elluviation.

The most interesting feature of this section was the substantial presence of muck (saprist), hemist, and fibrist histosol, including what appeared to be ‘pure’, non-mineral fibrist at ΠB12U. This histosol was present throughout the upper portion of Π, but suddenly disappeared in both rows and transitioned to sand in the last two points (ΠA16, ΠA17, ΠB15, and ΠB16).

A fascinating portion of this feature was related to the almost bog-like conditions found midway through the northern section, especially mid-way up the edge road (standing water). Here was a consistent phenomenon: the muck was a superficial layer 10-25cm thick, underlaid by a highly compacted , 5-15cm thick layer of clay; this combination might be causing the drainage issues. This clay layer is, however, underlain by a hardened red sand layer similar to the illuviated layers found on the rest of the farms, but usually not seen until 25-35 cm.

All clay I have seen is white-grey in color.

λH02, best example of farmed muck; ΠB12U best example of natural muck/fibrist (like Minnesota Histosol).

Bands of small, weaker timothy (1-2 ft tall, yellow coloration) with bog-like moss ground cover are interspersed with thick, lush stands of timothy (3-5 ft tall, deep green coloration) with little ground cover other than timothy.

Soils in the thin patches were generally less black, had a thinner A layer with more illuviated subsoil of a bright orange color, sandier, and were also on slightly higher terrain.

Soils in the thick patches were much more black, with a thicker A layer (15-25cm), more organic matter in the B layer, a darker line sometimes to the sandy portions of the B layer, and more often had clay (always white) as well as an elluviated layer (giving the appearance of a mollisol rather than a podzol). This lush layer was also much more infested by insects; Jamie noted that this might be due to black flies and mosquitoes being attracted to carbon emissions (i.e. usually emitted by their prey). Hence, high C soils with high respiration emitted more C and thus attracted insects.

This rump section was sampled so I could understand two things: a) what the composition of the ‘pure’ histosol was post-conversion but pre-agriculture (A01), and b) to understand the underlying mineral component of this histosol (A02, A03).

I noticed that in the majority of the area, the (shallow) organic material (mostly sphagnum moss) was completely pushed off the surface of the soil into rows on the sides of the field, leaving only sand in its place. However, despite being a year since clearing, and without any active management, this sand was not regrowing any plants! Only blueberries/raspberries seemed to be struggling to colonize the surface, but most of the sand was bare.

I hypothesize that the vast majority of the C in this soil was in the organic material pushed to the side, leaving a very poor, C-depleted soil incapable of sustaining any life. Given that this conversion practice is the standard across the Canadian boreal regions, this has disturbing implications for agricultural potential in these regions.

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